There are two ways to disable Samsung Device app. You can either disable it without affecting Dropbox or from the Dropbox website. If you want to disable the Samsung Device app from the Dropbox website, then sign in to your Dropbox website account security tab. Find the Samsung Device app located under the "App linked". Click "x" sign located at the right side of the 'Samsung Device'. This is how you can disable or disconnect Samsung Device app from the Dropbox website.